Freezer thaw alarms



Aug.19,1969 HJ. UNDER 3,461`g'a34 FREEZER THAW ALARMS Filed Sept. 18. 1968 1NVENTOR. Howard F? Linder ArroRNE'Y United States Patent O 3,461,834 FREEZER THAW ALARMS Howard P. Linder, P.0. Box 777, R.R. 5, Golden, Colo. 80401 Filed Sept. 18, 1968, Ser. No. 760,504 Int. Cl. G08b 17/00, 17/04, 21/00 U.S. Cl. 116-106 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to means for giving an advance warning that the temperature in a food storage freezer is approaching a thawing point so that steps can be taken to prevent spoilage of the food before damaging thawing occurs.

Many thermostatically controlled electrical devices have been commercially used on large refrigeration installations for giving signals when critical temperatures are approaching, but these devices are exceedingly complicated and expensive and are not feasibly adaptable to the relatively small, relatively inexpensive household freezers which are presently popular.

The principal object of this invention is to provide a simple, inexpensive, self-energizing, thaw alarm device, which will not require any electrical connections or other installation requirements, which can be simply placed in the food compartment of a freezer, without any changes in or attachments to the freezer, and which will give an alarm should the temperature in the compartment approach a thawing point.

It is possible, more especially with household freezers, that no one would he present when an audible alarm occurs and the Value of the alarm would be lost. Therefore, another object of this invention is to combine with an audible signal an automatic visual signal which when actuated will remain in signalling position to call the attention of the user to the freezer.

IOther objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and eiciency, These will become more apparent from the following description.

In the following detailed description of the invention, reference is made to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

FIG. 1 illustrates the elements of one form of the freezer thaw alarm of this invention as they would appear when assembled ready to be placed in a conventional food freezer;

FIG. 2 is an enlarged longitudinal section through a pressure bottle employed in the alarm, taken on the line 2-2, FIG. 1;

FIG. 3 is a fragmentary section of the upper portion of a conventional freezer showing its top at 10, door at 11 and door gasket at 12;

FIG. 4 is an enlarged detail section through an audible alarm device taken on the line 4--4, FIG. 1; and

FIG. is a fragmentary detail view, partially in section showing an alternate form of the invention.

3,461,834 Patented Aug. 19, 1969 ice Briefly, the alarm comprises a sealable metallic pressure bottle 1-3 from which a ilexible hose 14 extends to a pressure-actuated alarm device 15. The hose 14 communicates with a discharge tube 16 which extends to the bottom of the bottle. A cake of ice is frozen in the bottom of the bottle and forms an ice-seal 17 for the discharge tube 16. Gas is compressed in the upper portion of the bottle as indicated at 18. The gas cannot flow through the discharge tube 16 and the hose 14 to the alarm device 15 due to the ice-seal 17. In use, the bottle 13 is placed in the food compartment of the freezer and the alarm device 15 positioned exteriorally thereof with the hose 14 passing through between the top 10 and the door 11. The compressi-ble door gasket 12 allows free passage of the hose.

As long as the temperature in the food compartment remains below the melting point of the ice-seal 17 the device remains static. However, should the temperature rise above the melting point of the ice-seal 17, the latter will begin to melt. When it has melted sufliciently to allow the passage of fluid, the gas 18, which is exerting constant pressure on the melting uid, will force the latter into the discharge tube 16 and through the hose 14 to the alarm device 1S to actuate the latter.

The fluid from which the ice-seal 17 is frozen preferably has a freezing point below that of water so that it will melt and pass the gas before the compartment temperature reaches the thaw point so as to give advance warning before spoilage occurs. An aqueous sugar solution of 20% by weight of sugar appears to start to melt at approximately 5 Fahrenheit which provides a satisfactory warning interval. The gas 18 may be compressed air, Freon, CO2, or any other non-toxic gas. As illustrated, the alarm is designed for compressed air use.

For compressed air use, the bottle 13 is provided with an internally threaded neck 19 into which a rubber or plastic plug 20 is threaded against a sealing gasket 21. A threaded valve tube 22 is threaded through or molded in the plug 20 so as t0 project above and below the latter. The valve tube 22 may be a conventional automotive tire valve, provided with the usual internal spring-actuated check valve, the stem of which protrudes above the tube as indicated at 23. Gas cannot pass upwardly through the tube 22 unless the stern 23 is depressed as is customary with tire valves.

For the present use, a coupling 24 is threaded on the tire valve tube 22 in the place of the customary tire valve cap, and the coupling is provided with an internal protuberance 25 which depresses the valve stern 23 and maintains the check valve open when the discharge tube is closed by the ice-seal 17. The coupling is provided with a conventional hose nipple 26 upon which the hose 14 is mounted and sealed.

To prepare for use, the coupling 24 is unscrewed and the plug 20 is removed from the bottle. The ice-seal-forming iluid is then poured into the bottle to partially fill the latter, as shown in FIG. 2, and a compressed air hose, such as a lling station hose or a tire pump hose, is pressed against the ,upper extremity of the valve 22 to fill the remaining space in the bottle with air at the desired pressure and the conventional check valve in the tube 22 retains the compressed air in place. The bottle is now placed in a conventional freezer to freeze the fluid therein to form the ice seal 17, after which the bottle is ready for use.

For use, the coupling 24 is threaded into place, so as to attach the hose 14 and open the check valve in the valve tube 22, and the bottle is placed in the food compartment of the freezer with the hose 14 extending to the alarm device 15 at any convenient point on the exterior. The bottle may be simply set in any convenient position in the freezer compartment. `However, it is preferred to attach a resilient spring clamp beneath the top of the compart- E ment, as shown at 37 in FIG. 3, into which the bottle may be resiliently snapped for easy replacement.

The alarm device may have any structure suitable for the desired purpose. A preferred structure is illustrated in the drawing employing a horn tube 27, to which the free extremity of the hose 14 is attached and sealed. The horn tube is provided with a vibrating reed 28, such as used on musical instruments of the reed type. A conical horn bell 29 is formed on and projects its larger extremity forwardly about the horn tube 27. The large open forward extremity of the bell 29 is closed by means of a circular, frangible, cup-shaped, rubber or liexible plastic diaphragm 30 which is fitted over, and held in place on, the bell by means of a resilient band or O-ring 31 which annularly compresses the band into a circumferential receiving groove 32 in the bell. The diaphragm 30 is preferably lettered with the word SAFE It can be seen that should the ice-seal be melted by excess temperature in the food compartment, the liquid and the air blast from the bottle will be forced through the horn tube 27 past the reed 28 to create pressure in the horn bell 29 so as to distend or blow-up the diaphragm 30 so that an instantaneous audible signal will be given followed by an audible tone from the reed 28. A visible signal will also be given by the complete removal of the word SAFE and the residual discharge of the liquid from the melted ice-seal.

As above described, the gas pressure is placed in the bottle from an outside pressure source. The pressure on the solution could be obtained in any convenient suitable manner such as by elervescent CO2 tablets, or by rising a pre-pressurized can 33, such as indicated in FIG. 5, similar to the cans used for the gas dispersion of paints, insecticides, etc. Such cans have a tubular valve stem 34 projecting upwardly from the lid which corresponds to the valve stern 23 above described and which, when depressed, releases the pressurized solution which in this case would be the above described low-freezing-point solution.

To apply this invention to such a can the hose leading to the alarm-device, indicated at 36, would be provided with an inverted-cup-shaped, resilient, coupling 35 which would be resiliently snapped onto the conventional can cap to maintain the stem 34 in the open position, after the ice-seal had been formed.

While a speciiic form of the invention has been described and illustrated herein, it is to be understood that the same may be varied within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention what is claimed and desired to be secured by letters Patent is:

1. Means for giving an alarm to indicate that the temperature in a freezer compartment is approaching a thawing point comprising:

(a) a bottle, adapted to be placed in said compartment;

(b) a plug sealing the top of said bottle;

(c) a discharge conduit having its intake extremity positioned adjacent the bottom of said bottle and extending through said plug to the exterior of said bottle;

(d) a frozen uid partially filling said bottle and forming an ice-seal closing said intake extremity;

(e) a pressurized gas in said bottle exerting pressure on said ice seal; and

(f) a pressure-actuated alarm device connected to said discharge conduit so as to be actuated by said gas in consequence of the melting of said ice seal.

2. Means for giving an alarm as described in claim 1 in which the frozen-Huid has a melting point below that of water so that said ice-seal will melt to release said gas and actuate said alarm device before thawing occurs in said compartment.

3. Means for giving an alarm as described in claim 2 in which the connection between said alarm-device and said discharge conduit comprises:

(a) an elongated flexible hose communicating at its intake extremity with said discharge conduit and at its discharge extremity with said alarm device, said hose being suiciently long to allow said alarm device to be positioned exteriorly of said compartment when said bottle is in place therein.

4. Means for giving an alarm as described in claim 3 having:

(a) a spring-loaded check valve in the ow patch through the discharge conduit acting, when closed, to prevent ilow to said alarm device; and

(b) means for automatically opening said check valve in consequence of the connection of said exible hose to said discharge conduit.

5. Means for giving an alarm .as described in claim 4 in which the means for opening said check valve comprises:

(a) an axially-projecting valve-opening stem on said check valve;

(b) a coupling-element on said flexible hose connecting the latter to said discharge conduit; and

(c) an abutment in said coupling element positioned to contact and actuate said stem to open said check valve when said coupling element is in the coupled position.

6. Means for giving an alarm as described in claim 3 in which the alarm device comprises:

(a) an air-actuated, sound-producing element.

l 7. Means for giving an alarm as described in claim 3 in which the 4alarm device comprises:

(a) an air chamber to which said hose communicates;

and

(b) a frangible element closing one side of said chamber which will break away when the pressure in said chamber reaches a certain point to give a visual signal that said ice-seal is melting.

8. Means for giving an alarm as described in claim 6 having:

(a) an air chamber surrounding said sound producing element; and

(b) a frangible element closing one side of said chamber which will break away when the pressure in said chamber reaches a certain point to give a visual signal that said ice-seal is melting.

References Cited UNITED STATES PATENTS 2,334,095 11/1943 Hoghaug 116-34 2,362,398 11/1944 Pittman 116-1145 2,575,908 11/1951 Clifford.

2,741,099 4/1956 Beane 62-127 XR 2,764,121 9/1956 Showstack 116-106 2,788,282 4/1957 Hammond 116-106 XR 2,799,239 7/ 1957 Messick 116-106 3,299,960 1/1967 Stern 169-23 D LOUIS J. CAPOZI, Primary Examiner U.S. C1. X.R. 

